The question, Mr de Rivaz says, should be whether nuclear is competitive with the other technologies. “The job I have to do before the end of the year is to give the answer to this question and I believe I can deliver,” he says. “We will deliver.”

Not only is the EDF Energy chief attempting to deliver the first new British nuclear plant in more than two decades - but the 58-year-old Frenchman also wants the project to achieve the same bold aims as the London Olympics.

“The motto of the Games is 'inspiring a generation’,” he says, in thick Gallic tones. “With nuclear, I have the same ambition. Inspiring a generation of young people who will be attracted by this industry: by the skills, by the engineering, by what it takes to be at the top of a large industrial project of that nature.”

French-owned EDF Energy is, coincidentally, an official sponsor of the Olympics. Mr de Rivaz describes his own decision in 2004 to back London’s bid as nothing short of a “masterstroke”.

It is the last Thursday of the Games, and we are perched on the orange and white stools of EDF’s pavilion in the Olympic Park, looking across to the Stadium opposite. Cheers and music waft over from the athletics.

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“I don’t know if there is a word which is encapsulating enough what I feel,” he declares. “I am absolutely delighted, amazed and very proud.”

He has made it to see a few events, including watching Team GB beat France to gold in the velodrome. So who was he cheering for? “I am a Londoner and I have no problem to cheer for the winner,” he says, with a certain evasiveness.

But there’s no doubt EDF’s nuclear plans are consuming most of Mr de Rivaz’s time. They are now nearing a critical juncture: by the end of the year, he must present the EDF board and partner Centrica with a “compelling business case” to invest more than £10bn in building two nuclear reactors at Hinkley Point in Somerset.

“The vision was there to say the Olympics in 2012 will be a transforming event for the country,” he says. “The vision is there for nuclear, to say it will be a transforming event for the energy landscape in this country. We have to execute as well as all these remarkable people have done for London 2012.”

“Clearly there are lessons to be learnt from Flamanville, lessons we are going to take into account, believe me, in our project in Hinkley,” Mr de Rivaz says. Flamanville started before it was ready, leading to “underestimation of cost, underestimation of timetable”, he says.

He declines to say how the cost of Hinkley will compare - reports suggest each reactor could be as much as £7bn - and says we should focus on the cost per megawatt hour (MWh) for electricity.

Nuclear and other new low-carbon power plants will be each be guaranteed a fixed 'strike price’ for the electricity they generate, receiving subsidies from all UK electricity consumers if the market price falls below that level. The strike price for Hinkley is currently under negotiation with the Government, and is subject to intense speculation.

The question, Mr de Rivaz says, should be whether nuclear is competitive with the other technologies. “The job I have to do before the end of the year is to give the answer to this question and I believe I can deliver,” he says. “We will deliver.”

He eventually confirms this means a strike price lower than the current £140/MWh cost of offshore wind.

But he declines to say whether it also means matching £100/MWh, the price that offshore wind is supposed to come down to by 2020 - around the time Hinkley Point may actually be completed. He stresses he considers factors such as job creation as relevant to nuclear’s “competitiveness”.

One thing’s for certain, he confirms, it won’t be as cheap as the £45/MWh EDF told investors in 2008 - the last time the company itself appears to have put a number on it. “A lot of things have changed: four years, inflation, cost of commodities, steel, concrete,” he says. “And it was based on Flamanville.”

The absence of public guidance on costs has given rise to criticism about a lack of transparency. Mr de Rivaz insists this is unwarranted. “Believe me, we are not going to strike a deal which will not be fair and balanced, simply because it will not work, it will be pyrrhic victory.”

One factor critical in determining costs will be construction. Mr de Rivaz warns of a “productivity” problem in the UK construction sector, arguing it has too much of a “hire and fire” culture.

“Look here,” he gestures at the Olympic park outside. “Everyone is smiling. On a construction site it should be the same.” He says he wants to strike a “new covenant” with the unions, promising skills and career development, and to show he “speaks the same language” on safety, incentives and remuneration.

This brings me onto the thorny subject of his own remuneration.

Francois Hollande’s administration has capped the pay of French public companies’ chief executives at 20 times their lowest paid worker. Henri Proglio, EDF group chief executive, has reportedly accepted a 70pc cut, to a level well below Mr de Rivaz’s own £1.3m pay package. Will the rule apply to EDF Energy? “I don’t know,” he says.

Is that not concerning, more than two months from Mr Proglio’s pay cut? Mr de Rivaz, not usually short for words, studies a crib sheet entitled 'key messages’ for a good ten seconds. “Does it really matter for you, this question?” he asks, sounding slightly pained.

Well, I venture, executive pay is a controversial subject. “I do not deny that is is an important question,” Mr de Rivaz concedes. “But I don’t want to be distracted by that. I don’t know which policy will apply. We will see.”

And will he remain committed to Hinkley Point either way? “Yes, yes, yes,” he insists. Then adds, once more for good measure: “Now is our time to inspire a generation.”